This application claims priority of China patent Application No. 99125566.6, filed on Dec. 6, 1999.
The present invention relates to a catalyst system for the (co)polymerization of olefins.
In recent years, a study of a catalyst for olefinic polymerization has been greatly developed and properties of the catalyst have been greatly improved. Meanwhile, olefinic polymerization catalysts with better properties are desired as the demand for the processability of the polymer product become higher and higher.
U.S. Pat. No. 4,784,983 discloses a catalyst system for olefinic polymerization comprising components (A), (B) and (C). Component (A) is prepared by dissolving a halide of magnesium in a solvent mixture of an organic epoxy compound and an organic phosphorus compound to form a homogeneous solution; mixing the homogeneous solution with a liquid halide of titanium; adding an auxiliary precipitant such as organic carboxylic acid anhydrides, organic carboxylic acids, ethers and ketones to form a precipitate; adding at least one polycarboxylic acid ester when the precipitate appears; and separating the precipitate from the mixture and treating the separated precipitate with the halide of titanium or a mixture of the halide of titanium in an inert diluent. The activity of the catalyst system of the patent is a very high. The resultant polymer using the catalyst system has very high stereospecificity and a narrow particle size distribution.
One main method of adjusting molecular weight of polypropylene is to introduce hydrogen gas into the polymerization system. When the catalyst system of U.S. Pat. No. 4,784,983 is used in the propylene polymerization, sensitivity of adjusting molecular weight of polypropylene with hydrogen gas is not ideal.
CN 1143651A disclosed solid catalyst components and catalyst therefrom. The catalysts comprise the reaction product of: (1) a solid catalyst component containing an internal electron-donor; (2) an Al-alkyl compound, and optionally (3) an external electron-donor. The catalyst obtained by using, as the external-electron donor, cyclopolyenic, 1,3-diethers exhibit in the polymerization of olefins very high balances of activity and stereosepcificity. But, when the catalysts are used in file polymerization of propylene, an external electron-donor must be added in order to obtain the polymer with stereospecificity of greater 99%. If no external electron-donor is used, stereospecificity of the resultant polymer can only be about 98%. However, when an external electron-donor is added in the polymerization of olefins, the sensitivity of active sites of the catalysts to hydrogen gas decreases, hydrogen gas adjustability on the molecular weight of polypropylene becomes bad and activity of the catalysts greatly decreases.
An object of the present invention is to provide a catalyst system for the (co)polymerization of olefins that overcome the above drawbacks in the prior art.
The present invention provides a catalyst system for the (co)polymerization of olefins, characterized in that it consists of the following components:
(A) A solid catalyst component comprising titanium, magnesium, halogen and a 1,3-diether and prepared by dissolving a halide of magnesium in a solvent system consisting of an organic epoxy compound, an organic phosphorus compound and optionally an inert diluent to form a homogeneous solution; mixing the homogeneous solution with titanium tetrahalide or its derivatives to form a mixture; precipitating a solid from the mixture in the presence of at least one auxiliary precipitant; treating the solid with the 1,3-diether to load the diether on the solid; and treating the diether loaded solid with the titanium tetrahalide or its derivatives and the inert diluent;
(B) An organic aluminum compound; and optionally
(C) An organic silicon compound.
The present invention is described in details as follows.
1. The halide of Magnesium solution
The halide of Magnesium solution herein means a uniform solution obtained by dissolving a halide of magnesium in a solvent system consisting essentially of organic epoxy compounds and organic phosphorus compounds. The solvent system may include inert diluents.
(1) Halide of magnesium
Suitable halide of magnesium includes magnesium halide such as magnesium chloride, magnesium bromide and magnesium iodide; a complex of magnesium halide with water or alcohol; a derivative of magnesium halide wherein a halogen atom is substituted by a hydrocarboxyl or halohydrocarboxyl group; and like.
(2) Organic epoxy compound
Suitable organic epoxy compound includes oxides of aliphatic olefins, aliphatic diolefins, halogenated aliphatic olefins, and halogenated aliphatic diolefins, glycidyl ethers, cyclic ethers and the like having 2-8 carbon atoms. Examples of suitable organic epoxy compounds are ethylene oxide, propylene oxide, butylene oxide, butadiene dioxide, epoxy chloropropane, methylglycidyl ether, diglycidyl ether, tetrahydrofuran, and the like.
(3) Organic phosphorus compounds
Suitable organic phosphorus compounds include hydrocarbon and halohydrocarbon esters of phosphoric acid or phosphorous acid, e.g. trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphite and the like.
(4) Preparation of the halide of magnesium solution
The particle size of the halide of magnesium used is preferred to be such that it is easily dissolved with stirring. The dissolution temperature is about 0xc2x0 C.-100xc2x0 C., preferably from 30xc2x0 C.-70xc2x0 C. Inert diluents such as hexane, heptane, octane, benzene, toluene, xylene, 1,2-dichloroethane, chlorobenzene and other hydrocarbons or halohydrocarbons can be added into the solvent system. The amount of epoxy compounds added is about 0.2-10.0 moles, preferably 0.5-4.0 moles, per mole of halide of magnesium, and the amount of organic phosphorus compounds added is about 0.1-3.0 moles, preferably 0.3-1.0 moles, per mole of halide of magnesium.
2. Precipitation of the solid
The halide of magnesium solution is maixed liquid titanium tetrahalide to form a solid precipitate in the presence of an auxiliary precipitant. 1,3-diether may be added before or after the precipitation of the solid and loaded on the solid.
According to the invention, the auxiliary precipitant can be added either after the halide of magnesium solution is obtained or together with the halide of magnesium. The liquid titanium tetrahalide or its derivatives can be in the pure liquid state, or in a solution of inert diluents.
(1) Titanium tetrahalide or its derivatives
The halide of titanium used in the preparation of the solid catalyst component (A) of the invention is a compound having the formula TiXn(OR)4-n wherein X is a halogen, each R is independently a hydrocarbyl and n is an integer of from 0 to 4. Examples of the compounds are titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, tetrabutoxy titanium, tetraethoxy titanium, chlorotriethoxy titanium, dichlorodiethoxy titanium, trichloroethoxy titanium and the like.
The halide of magnesium solution and liquid titanium tetrahalide or its derivatives used in the present invention have been disclosed in U.S. Pat. No. 4,784,983 which is incorporated herein by reference.
(2) 1,3-diether
The 1,3-diether used in this invention is selected from the compounds of the general formula: 
Where each R is independently hydrogen, halogen, linear or branched C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkaryl and C7-C20 aralkyl, with the proviso that all R cannot be hydrogen or CH3;
Each R1 is independently hydrogen, halogen, linear or branched C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkaryl and C7-C20 aralkyl;
Each R2 is independently hydrogen, halogen, linear or branched C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkaryl and C7-C20 aralkyl;
Two R can be bonded to each other to form saturated or unsaturated condensed cyclic structures, optionally substituted with a radical selected from the group consisting of halogen, linear or branched C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkaryl and C7-C20 aralkyl.
The 1,3-dietheris is used as internal electron-donor in the catalyst system of this invention.
Particularly preferred among 1,3-diether are the compounds of the formula: 
More preferred among the 1,3-diether are the compounds of the formula: 
In the above formulas, each R is independently hydrogen, halogen, linear or branched C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkaryl and C7-C20 aralkyl;
Each R1 is independently hydrogen, halogen, linear or branched C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkaryl and C7-C20 aralkyl;
Each R2 is independently hydrogen, halogen, linear or branched C7-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkaryl and C7-C20 aralkyl;
Two or more of R can be bonded to each other to form saturated or unsaturated condensed cyclic structures, optionally substituted with a radical selected from the group consisting of halogen, linear or branched C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkaryl and C7-C20 aralkyl.
Specific examples of 1,3-diether are:
2-(2-ethyl hexyl)-1,3-dimethoxypropane;
2-isopropyl-1,3-dimethoxypropane;
2-butyl-1,3-dimethoxypropane;
2-sec-bytyl-1,3-dimethoxypropane;
2-cyclohexyl-1,3-dimethoxypropane;
2-phenyl-1,3-dimethoxypropane;
2-cumyl-1,3-dimethoxypropane;
2-(2-phenyl ethyl)-1,3-dimethoxypropane;
2-(2-cyclohexyl ethyl)-1,3-dimethoxypropane;
2-(para-chloro phenyl)-1,3-dimethoxypropane;
2-(diphenyl methyl)-1,3-dimethoxypropane;
2-(1naphthyl)-1,3-dimethoxypropane;
2-(2-fluorophenyl)-1,3-dimethoxypropane;
2-(1-decahydronaphthalenyl)-1,3-dimethoxypropane;
2-(para-tert-butyl phenyl)-1,3-dimethoxypropane;
2,2-dicyclohexyl-1,3-dimethoxypropane;
2,2-dicyclopentyl-1,3-dimethoxypropane;
2,2-diethyl-1,3-dimethoxypropane;
2,2-dipropyl-1,3-dimethoxypropane,
2,2-diisopropyl-1,3-dimethoxypropane;
2,2-dibutyl-1,3-dimethoxypropane,
2-methyl-2-propyl-1,3-dimethoxypropane;
2-methyl-2-benzyl-1,3-dimethoxypropane;
2-methyl-2-ethyl-1,3-dimethoxypropane;
2-methyl-2-isopropyl-1,3-dimethoxypropane;
2-methyl-2-phenyl-1,3-dimethoxypropane;
2methyl-2-cyclohexyl-1,3-dimethoxypropane;
2,2-bis(p-chlorophenyl)-1,3-dimethoxypropane;
2,2-bis(2-cyclohexylethyl)-1,3-dimethoxypropane;
2-methyl-2-isobutyl-1,3-dimethoxypropane;
2-methyl-2-(2-ethylhexyl)-1,3-dimethoxypropane;
2,2-diisobutyl-1,3-dimethoxypropane;
2,2-diphenyl-1,3-dimethoxypropane;
2,2-dibenzyl-1,3-dimethoxypropane;
2,2-bis(cyclohexylmethyl)-1,3-dimethoxypropane;
2-isobutyl-2-isopropyl-1,3-dimethoxypropane;
2-(1-methyl butyl)-2-isopropyl-1,3-dimethoxypropane;
2-(1-methylbutyl-1)-2-sec-butyl-1,3-dimethoxypropane;
2,2-di-sec-butyl-1,3-dimethoxypropane.
2,2-di-tert-butyl-1,3-dimethoxypropane;
2,-2-di-neopentyl-1,3-dimethoxypropane;
2-isopropyl-2-isopentyl-1,3-dimethoxypropane;
2-phenyl-2-isopropyl-1,3-dimethoxypropane;
2-phenyl-2-sec-butyl-1,3-dimethoxypropane;
2-benzyl-2-isopropyl-1,3-dimethoxypropane;
2-benzyl-2-sec-butyl-1,3-dimethoxypropane;
2-phenyl-2-benzyl-1,3-dimethoxypropane;
2-cyclopentyl-2-isopropyl-1,3-dimethoxypropane;
2-cyclopentyl-2-sec-butyl-1,3-dimethoxypropane;
2-cyclohexyl-2-isopropyl-1,3-dimethoxypropane;
2-cyclohexyl-2-sec-butyl-1,3-dimethoxypropane;
2-cyclohexyl-2-sec-butyl-1,3-dimethoxypropane;
2-cyclohexyl-2-cyclohexyl methyl-1,3-dimethoxypropane;
1,1-bis(methoxymethyl)-cyclopentadiene;
1,1-bis(methoxymethyl)-2,3,4,5-tetramethylcyclopentadiene;
1,1-bis(methoxymethyl)-2,3,4,5-tetraphenylcyclopentadiene;
1,1-bis(methoxymethyl)-2,3,4,5-tetrafluorocyclopentadiene;
1,1-bis(methoxymethyl)-3,4-dicyclopentylcyclopentadiene;
1,1-bis(methoxymethyl)-indene;
1,1-bis(methoxymethyl)-2,3-dimethylindene,
1,1-bis(methoxymethyl)-4,5,6,7-tetrahydroindene;
1,1-bis(methoxymethyl)-2,3,6,7-tetrafluoroindene;
1,1-bis(methoxymethyl)-4,7-dimethylindene;
1,1-bis(methoxymethyl)-3,6-dimethylindene;
1,1-bis(methoxymethyl)-4-phentyindene;
1,1-bis(methoxymethyl)-4-phenyl-2-methylindene;
1,1-bis(methoxymethyl)-4-cyclohexylindene;
1,1-bis(methoxymethyl)-7-(3,3,3-trifluoropropyl)indene;
1,1-bis(methoxymethyl)-7-trimethylsilylindene,
1,1-bis(methoxymethyl)-7-trifluoromethylindene;
1,1-bis(methoxymethyl)-4,7-dimethyl-4,5,6,7-tetrahydroindene;
1,1-bis(methoxymethyl)-7-methylindene;
1,1-bis(methoxymethyl)-7-cyclopentylindene;
1,1-bis(methoxymethyl)-7-isopropylindene,
1,1-bis(methoxymethyl)-7-cyclohexylindene;
1,1-bis(methoxymethyl)-7-tertbutylindene;
1,1-bis(methoxymethyl)-7-tert-butyl-2-methylindene;
1,1-bis(methoxymethyl)-7-phenylinden;
1,1-bis(methoxymethyl)-2-phenylinden;
9,9-bis(methoxymethyl)-fluorene;
9,9-bis(methoxymethyl)-2,3,6,7-tetramethylfluorene;
9,9-bis(methoxymethyl)-2,3,4,5,6,7-hexafluorofluorene;
9,9-bis(methoxymethyl)-2,3-benzofluorene;
9,9-bis(methoxymethyl)-2,3,6,7-dibenzofluorene,
9,9-bis(methoxymethyl)-2,7-diisopropylfluorene;
9,9-bis(methoxymethyl)-1,8-dichlorofluorene;
9,9-bis(methoxymethyl)-2,7-diisopropylfluorene
9,9-bis(methoxymethyl)-2,7-dicyclopentylfluorene;
9,9-bis(methoxymethyl)-1,8-dichlorofluorene;
9,9-bis(methoxymethyl)-1,2,3,4-tetrahydrofluorene;
9,9-bis(methoxymethyl)-1,2,3,4,5,6,7,8-octahydrofluorene;
9,9-bis(methoxymethyl)-4-tertbutylfluorene;
1,1-bis(1xe2x80x2-butoxyethyl)-cyclopentadiene;
1,2-bis(1xe2x80x2-isopropoxy-n-propyl)cyclopentadiene;
1-methoxymethyl-1-(1xe2x80x2-methoxyethyl)-2,3,4,5-tetramethylcyclopentadiene;
1,1-bis(xcex1-metoxybenzyl)indene;
1,1-bis(phenoxymethyl)indene,
1,1-bis(1xe2x80x2-methoxyethyl)-5,6-dichloroindene;
1,1-bis(phenoxymethyl)-3,6-dicyclohexylindene;
1-methoxymethyl-1-(1xe2x80x2-methoxyentyl)-7-tert-butylindene;
1,1-bis[2-(2xe2x80x2-methoxypropyl)]-2-methylindene;
9,9-bis(xcex1-methoxybenzyl)fluorene;
9,9-bis(1xe2x80x2-isopropoxynbutyl-4,5-diphenylfluorene;
9,9-bis(1xe2x80x2-methoxyethyl)fluorene;
9-(methoxymethyl)-9-(1xe2x80x2-methoxyethyl)-2,3,6,7-tetrafluoroflurorene;
9-methoxymethyl-9-pentoxymethylfluorene;
9-methoxymethyl-9-ethoxymethylfluorene;
9-methoxymethyl-9-(1xe2x80x2-methoxyethyl)-fluorene;
9-methoxymethyl-9-[2-(2xe2x80x2-methoxypropyl)]-fluorene;
1,1-bis(methoxymethyl)-2,5-cyclohexadiene;
1,1-bis(methoxymethyl)benzonaphthene;
7,7-bis(methoxymethyl)-2,5-norbornadiene;
9,9-bis(methoxymethyl)-1,4-methanedihydronaphthalene;
9,9-bis(methoxymethyl)-9,10-dihydroanthracene;
1,1-bis(methoxymethyl)-1,2-dihydronaphthalene;
4,4-bis(methoxymethyl)-1-phenyl-3,4-dihydronaphthalene;
4,4-bis(methoxymethyl)-1-phenyl-1,4-dihydronaphthalene;
5,5-bis(methoxymethyl)-1,3,6-cycloheptatriene.
(3) Auxiliary precipitant
The auxiliary precipitant according to this invention includes organic acid anhydrides, organic acids, ketones, aldehydes, ethers and any combination thereof, such as acetic anhydride, phthalic anhydride, succinic anhydride, maleic anhydride, pyromellitic dianhydride, acetic acid, propionic acid, butyric acid, acrylic acid, methacrylic acid, acetone, methyl ethyl ketone, benzophenone, dimethyl ether, diethyl ether, dipropyl ether, dibutyl ether, diamyl ether, 1,3-diether and the like.
The step of treating the solid may be omitted when the auxiliary precipitant comprises the 1,3-diether.
(4) Precipitation of the solid
The process of solids precipitation can be carried out by one of two methods. One method involves mixing liquid titanium tetralalide with a halide of magnesium at a temperature in the range of about xe2x88x9240xc2x0 C. to 0xc2x0 C., and precipitating the solids while the temperature is raised slowly. The other method involves adding liquid titanium tetrahalide dropwise into the homogeneous halide of magnesium solution at room temperature to precipitate out solids immediately, In both methods, an auxiliary precipitant must be present in the reaction system. The auxiliary precipitant can be added before or after precipitation of the solid.
In order to obtain uniform solid particles, the process of precipitation should be carried out slowly. When the second method of adding titanium halide dropwise at room temperature is applied, the process should preferably take place over a period of from about 1 hour to 6 hours. When the first method of raising the temperature in a slow manner is applied, the rate of temperature increase preferably ranges from about 4xc2x0 C. to about 100xc2x0 C. per hour.
The mole ratios of various components per mole of magnesium halide in this step are as follow: titanium halide, 0.5-150, preferably 1-20 and auxiliary precipitant, 0.03-1.0, preferably 0.05-1.4.
3. Treatment and washing of the solid precipitate
The solid precipitate is first separated from the mixture. In the solid precipitate thus obtained is entrained a variety of complexes and impurities, so that further treatment is necessary.
The solid precipitate are treated with titanium tetrahalide or a mixture of titanium tetrahalide and an inert diluent and then washed with an inert diluent. The amount of titanium tetrahalide used is 1 to 20 moles, preferably 2 to 15 moles, per mole of halide of magnesium. The treatment temperature ranges from 50xc2x0 C. to 150xc2x0 C., preferably from 60xc2x0 C. to 100xc2x0 C. If a mixture of titanium tetrahalide and inert diluent is used to treat the solid precipitate, the volume % of titanium tetrahalide in the treating solution is 10-100 percent, preferably 20-80 percent, the rest being an inert diluent.
The treated solids are further washed with an inert diluent to remove ineffective titanium compounds and other impurities.
Component (A) according to the present invention thus obtained through the above described steps 1, 2 and 3, can be used as a solid or as a suspension.
4. Polymerization of xcex1-olefin
The catalyst system according to this invention consists of components (A), (B) and optionally (C).
(1) Organic aluminum compound
Component (B) is an organic aluminum compound having the formula AlRnxe2x80x2 X3-nxe2x80x2 wherein each R is independently hydrogen, or a hydrocarbon group having 1-20 carbon atoms, preferably an alkyl, aralkyl or aryl group; X is a halogen, preferably chlorine or bromine; and nxe2x80x2 is a number of from 1 to 3. Examples of the compounds are trialkyl aluminums such as trimethyl aluminum, triethyl aluminum, tri-isobutyl aluminum and trioctyl aluminum; hydrogenated alkyl aluminums such as diethyl aluminum hydride and di-isobutyl aluminum hydride; halogenated alkyl aluminums such as diethyl aluminum chloride, di-isobutyl aluminum chloride, sesquitectyl aluminum sesquichloride and ethyl aluminum dichloride; with triethyl aluminum and tri-isobutyl aluminum being preferred.
(2) Organic silicon compound
Component (C) is an organic silicon compound having the formula Rnxe2x80x2 Si(ORxe2x80x2)4-nxe2x80x2 wherein nxe2x80x2 is an integer of from 0 to 3; R and Rxe2x80x2 each is independently is alkyl, cycloalkyl, aryl, or haloalkyl group. Examples of such compounds are trimethlyl methoxysilane, trimethyl ethoxysilane, methyl cyclohexyl dimethoxy silane, dibutyl dimethoxy silane, dimethyl dimethoxysilane, dimethyl diethoxysilane, diphenyl dimethoxysilane, diphenyl diethoxysilane, phenyl triethoxysilane, pheyl trimethoxysilane, and the like. Component (C) may be replaced with 1,3-diether.
In the catalyst system of the invention, the molar ratio of aluminium in component (B) to titanium in component (A) is from 5 to 1000, preferably from 100 to 800, and the molar ratio of silicon in component (C) to titanium in component (A) is from 2 to 100, preferably from 8 to 32.
Components (B) and (C) have been disclosed in U.S. Pat. No. 4,784,983 which is incorporated herein by reference.
(3) xcex1-olefins
It is suitable to employ the catalyst system of this invention in the polymerization of xcex1-olefins, e.g. ethylene, propylene, 1-butylene, 4-methyl-1-pentene, 1-hexylene, 1-octylene and the like. Homopolymerization as well as atactic copolymerixation and block copolymerization of these olefins can be carried out using the catalyst system of the resent invention. Conjugated diene or nonconjugated diene can be selected as a monomer in copolymerizaiton.
Liquid-phase polymerization and gas-phase polymerization can both be employed. An inert solvent selected from saturated aliphatic or aromatic hydrocarbons such as hexane, heptane, cyclohexane, naphtha, extract oil, hydrogenated gasoline, kerosene, benzene, toluene and xylene can be used as the reaction medium in liquid-phase polymerization. The olefin itself can also act as the reaction medium. Prepolymerization can be conducted before polymerization. Polymerization can be carried out in batch mode, semi-continuous or continuous mode.
The polymerization takes place at a temperature ranging from room temperature to about 150xc2x0 C., preferably from about 50xc2x0 C. to 100xc2x0 C. Hydrogen gas can be used as a molecular weight regulator.
In comparison with the prior art, the catalyst system of the present invention when used in the polymerization of propylene has significant advantages as follows:
1. The activity of the catalyst system of this invention, due to incorporation of the 1,3-diether, is greatly improved.
2. When the catalyst system of this invention is used in the propylene polymerization, sensitivity of adjusting the molecular weight of polypropylene with hydrogen gas is excellent.
3. Stereospecificity of the polymer obtained by using the catalyst system of this invention is from 92% to 99.9%.
4. When the catalysts of CN 1143651A are used in the polymerization of propylene, an external electron-donor must be added in order to obtain the polymer with stereospeificity of greater than 99%. If no external electron-donor is used, stereospecificity of the resultant polymer can be only about 98%. However, when an external electron-donor is added in the polymerization of olefins, the sensitivity of active sites of the catalysts to hydrogen gas decreases, hydrogen gas adjustability on the molecular weight of polypropylene becomes bad and activity of the catalysts greatly decreases.
Stereospecificity of the polymer prepared by using the catalyst system of this invention even containing no external electron-donor is greater than 99%. Also, the activity of the catalyst system and hydrogen gas adjustability on the molecular weight of the polymer do not significantly decrease.
In order that the invention may be more fully understood, the following Examples and Comparative Examples are given by way of illustration only.